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4-1 Chapter 4 Hardware: The CPU & Storage 4.1 Microchips, Miniaturization, & Mobility 4.2 The System Unit: The Basics 4.3 More on the System Unit 4.4 Secondary Storage 4.5 Future Developments in Processing & Storage McGraw-Hill/Irwin © 2007 The McGraw-Hill Companies, Inc. All rights reserved. Microchips, Miniaturization, & Mobility Vacuum Tubes vs. Transistors Vacuum tubes were the original logic gates of computers They looked like light bulbs, were hot, and burned out like them too The original transistors were 1/100th the size of vacuum tubes (less power, faster, more reliable too) Transistors vs. Integrated Circuits Compare 1955’s 45 lb “portable” color TV to today’s 7 oz Casio 2.3 inch color TV One integrated circuit contains thousands of transistors 4-3 Microchips, Miniaturization, & Mobility Semiconductor A material whose electrical properties are intermediate between a good conductor and a nonconductor of electricity Perfect substrate to overlay complex circuits on Microchips are made from semiconductors Contain millions of microminiature integrated circuits 4-4 Microchips, Miniaturization, & Mobility Microprocessor The miniaturized circuitry of an entire computer processor on a single chip Contains the CPU, which processes data Microcontroller or Embedded Computer A microprocessor that was modified for use in a machine that isn’t a computer 4-5 The System Unit: The Basics Binary System: the basic unit of computing Uses just two numbers: 0 and 1 All data and program instructions in the computer are represented as binary Bit: each 0 or 1 is a bit Byte: a group of 8 bits Kilobyte: ~1,000 (1,024) bytes Megabyte: ~1 Million (1,048,576) bytes Gigabyte: ~1 Billion (1,073,741,824) bytes Terabyte: ~ 1 Trillion (1,009,511,627,576) bytes Petabyte: ~ 1 quadrillion bytes Exabyte: ~ 1 quintillion bytes All the printed material in the world is ~ 5 exabytes 4-6 The System Unit: The Basics Binary coding schemes assign a unique binary code to each letter EBCDIC Requires 8 bits per character Used for IBM mainframes ASCII Requires 7 or 8 bits per character, depending on the version 8 bit Extended ASCII provides 256 characters Used for PCs, Unix hosts, Macs Unicode Requires 16 bits per character Handles 65,536 characters 4-7 The System Unit: The Basics Error Checking: Parity Bits Used in modems & communications to verify correctness One check bit is added to 7 bit byte The check bit is defined as either odd or even For odd parity, if the data sent is correct, the parity bit plus the first 7 data bits is an odd number For even parity, if the data sent is correct, the parity bit plus the first 7 data bits is an even number Discussion Question: If the 7 data bits are 1101011, and the modem is sending odd parity, what should the parity bit be set to? Answer: Since the data bits add up to 5, an odd number, the parity bit will be 0. 4-8 The System Unit: The Basics Machine Language A binary-type programming language built into the CPU that is run directly by the computer Each CPU type has its own machine language Language Translators System programs convert the programming instructions for you into machine language 4-9 The System Unit: The Basics 4-10 The System Unit: The Basics Computer Terms Names 1. Bay 2. 3. 4. 5. 6. 7. 8. Definitions 1. 2. Power Supply Surge Protector 3. Voltage Regulator UPS 4. 5. 6. Motherboard Microprocessor 7. 8. Chipset Shell or opening used for the installation of electrical equipment. This converts AC to DC to run the computer. Protects the computer from being damaged by power spikes. Plug your computer into one. Protects a computer against brownouts or low power conditions that happen a lot in summer. Uninterruptible Power Supply. Battery-operated device that provides power for a time when there is a blackout. The main system board of the computer. The miniaturized circuitry of a computer processor. Groups of interconnected chips on the motherboard that control information flow between the microprocessor and other system components connected to the motherboard. 4-11 The System Unit: The Basics The CPU Older CPUs processing speeds are in MegaHertz 1 MHz = 1 Million ticks per second Current CPUs processing speeds are in GigaHertz 1 GHz = 1 Billion ticks per second The faster a CPU runs, the more power it consumes, and the more heat it generates 4-12 The System Unit: The Basics The CPU Continued Mainframe and minicomputer speed is measured in MIPS MIPS stands for millions of instructions per second Workstations perform at 100 MIPS or more Mainframes perform at 200 – 1,200 MIPS Supercomputer processing speed is measured in flops Flops stands for floating point operations per second IBM’s Blue Gene/L cranks out 70.72 teraflops (tera = trillion) per second 4-13 More on the System Unit Parts of the CPU Definition 1. Name Word size 2. Control unit 2. The part of the CPU that deciphers instructions and carries them out 3. 3. The ALU performs mathematical and logical operations and controls the speed of them 4. Arithmetic Logic Unit Registers 5. Buses 5. Electrical data roadways used to transmit bits within the CPU and between CPU and other motherboard components 1. The number of bits the processor can process at any one time 4. High-speed storage areas that temporarily store data during processing 4-14 More on the System Unit How Memory Works 1. Memory Chip RAM 1. 2. ROM 2. 3. CMOS 3. 4. Flash 4. Explanation Random Access Memory chips are volatile and hold: a. Software instructions b. Data before & after the CPU processes it Read only memory a. Cannot be written on or erased without special equipment b. Are loaded at factory with fixed start-up instructions Complementary Metal Oxide Semiconductor a. Powered by a battery b. Contains time, date, calendar, boot password Nonvolatile memory that can be erased and reprogrammed more than once a. Doesn’t require a battery b. Used in newer PCs for BIOS instructions 4-15 More on the System Unit Types of RAM RAM Types 1. DRAM 2. SDRAM 3. SRAM Explanation 1. Dynamic RAM must be constantly refreshed by the CPU or it loses its contents Synchronous Dynamic RAM is synchronized by the system clock and is much faster than DRAM 3. Static RAM is faster than DRAM and retains its contents without having to be refreshed by CPU 2. Double-data rate synchronous dynamic RAM 5. Single Inline Memory Module has RAM chips on only one side 4. 4. 6. FPM is fast page mode type b. EDO is extended data output; is faster than FPM 6. Dual Inline Memory Module has chips on both sides DDR-SDRAM 5. SIMM a. DIMM 4-16 More on the System Unit Speeding up Processing The CPU works much faster than RAM So it could sit there waiting for information Cache temporarily stores instructions and data that the processor uses frequently to speed up processing Level 1 cache is part of the microprocessor Holds 8 to 256 kb Faster than Level 2 cache Level Holds 64 kb to 2 Mb Level 2 cache is SRAM external cache 3 cache is on the motherboard Comes on very high-end computers 4-17 More on the System Unit Speeding up Processing Method 1. Interleaving 2. Bursting 3. Pipelining Superscalar Architecture 5. Hyperthreading 1. 2. 3. 4. 4. 5. Description CPU alternates communications between two or more memory banks CPU grabs a block of data from memory instead of retrieving one piece at a time CPU doesn’t wait for one instruction to complete before fetching its next instruction The computer can execute more than one instruction per clock cycle A technique used in superscalar architecture in which the OS treats the microprocessor as though it is two microprocessors 4-18 More on the System Unit Ports Port Type 1. Serial Port 2. Parallel Port 3. SCSI Port 4. USB Port Description Used to transmit slow data over long distances a. Sends data sequentially, one bit at a time b. Used to connect keyboard, mouse, monitors, dial-up modems 2. For transmitting fast data over short distances a. Transmits 8 bytes simultaneously b. Connects printers, external disks, backups 3. Small Computer System Interface a. Connects up to 7 devices in a daisy chain b. Transmits data 32 bits at a time 4. Universal Serial Bus can theoretically connect up to 127 peripheral devices in a daisy chain 1. 4-19 More on the System Unit USB Goals Be low-cost Be able to connect lots of devices Be hot swappable People hate rebooting because it takes time Hot swapping means a device can be connected/disconnected without rebooting Permit plug and play Devices are automatically configured when they are installed – no need to download new drivers 4-20 More on the System Unit USB Continued Standards 1.1 – the original standard USB 2.0 – the current standard for new PCs USB On The Go (OTG) – currently under development USB Connectors A – in USB Type 1.1 and 2.0 B – in USB Type 1.1 and 2.0 Mini B – in USB Type 2.0 Mini A – in USB OTG used for smaller peripherals like cellphones 4-21 More on the System Unit Specialized Expansion Ports Port Type 1. FireWire Description 1. Intended for devices working with lots of data a. 2. MIDI b. 2. Musical Instrument Digital Interface a. 3. IrDA 4. Bluetooth b. Infrared Data Association: Infrared ports used to make a cableless connection 4. Uses short-range radio waves that transmit up to 30 ft b. Ethernet Connects musical instruments Used in creating, recording, editing, performing music 3. a. 5. Used for camcorders, DVD players, TVs Handles up to 400 megabits per second 5. Connects computers to printers, keyboards, headsets, even refrigerators Named after King Harald Bluetooth, son of Gorm, who united the Norway and Denmark. Ruled 910-940 A.D. The standard for linking all devices in a Local Area Network 4-22 More on the System Unit Expansion Cards 4-23 More on the System Unit Expansion Buses Bus 1. PCI bus 2. AGP Bus Description 1. Peripheral Component Interconnect a. For high-speed connections b. 32 or 64 bits wide c. Typically used for sound cards, modems, high-speed network cards 2. Accelerated Graphics Port a. Twice the speed of PCI bus b. For Video and 3-D graphics cards 4-24 Secondary Storage Storage Types 1. Floppy and Zip disks Descriptions 1. Removable disks. Floppies store 1.44 MB b. Zip disks store 100, 250, or 750 MB Made from thin rigid metal covered with magnetizable substrate. Most disks have 2 or more platters Removable CDs and DVDs Thin plastic tape coated with magnetizable substance Like a credit card, but contains a microprocessor and memory chips Nonvolatile memory – no moving parts Lets you store data on an online vendor’s server a. Hard disks 2. Optical disks 4. Magnetic tape 3. 2. 3. Smart Cards 6. Flash memory 7. Online secondary storage 5. 4. 5. 6. 7. 4-25 Secondary Storage Floppies and Zip Disks Floppies Flat piece of mylar plastic inside a 3.5” plastic case Store about 1.44 MB Have a write-protect notch Data is recorded in tracks: concentric recording bands Formatting breaks the tracks into small wedge-shaped sectors Read/Write head transfers data between the computer and disk Floppies DO wear out! Zip Disks Disks with a high-quality magnetic coating Store 100, 250, or 750 MB Require a Zip drive; won’t work on floppy drives Used to store larger files than floppies can hold Zip disks wear out too! 4-26 Secondary Storage Hard Disks Thin, rigid metal, glass, or ceramic platters covered with a substance that allows data to be held in the form of magnetized spots The more platters there are, the higher the drive capacity Store data in tracks, sectors, and clusters Formatting creates a file allocation table that maps files to clusters or inodes Typical file systems are VFAT & NTFS for Windows, HFS and ext2 for Unix Drive heads ride on .000001” cushion of air, and can crash! Important data should always be backed up! 4-27 Secondary Storage Hard Disks Hard Disk Types: Hard Disks – a freestanding disk drive Removable Hard Disk – inserted into a cartridge drive on the PC External Hard Disk Controllers EIDE – Enhanced Integrated Drive Electronics Supports up to 4 disks at 137 GB per disk Marketed as SATA, Fast ATA, Ultra ATA, ATA-2, ATA/100 – Faster than EIDE controllers Fibre Channel – used in large servers – faster and costlier than SCSI 4-28 SCSI Secondary Storage Optical Disks CDs and DVDs are Optical disks Data is written and read using lasers, not a disk head CD-ROM is Compact Disk Read-Only Memory CD-R is used for recording only once CD-RW is an erasable optical disk that can both record and erase data over and over again DVD is a CD-style disk with extremely high capacity Stores 4.7 or more GB DVD-R is used for recording only once DVD-RW, DVD-RAM, DVD+RW are reusable DVDs 4-29 Secondary Storage Magnetic Tape Thin plastic tape coated with a substance that can be magnetized Store 200 GB and higher Used in the form of tape cartridges Still popular for large backups because of their large data capacity But don’t get it near a magnet as that will erase it! 4-30 Secondary Storage Smart Cards Resembles a credit card, but contains a microprocessor and memory chips Holds more information than standard magnetic-strip credit cards; 8 – 40 MB of data UltraCard Uses a magnetic shim that draws out of the card to be read, then retracts into the drive Provides 2 GB of storage Contact smart cards Must be swiped through card readers Can wear out from use Contactless smart cards Read when held in front of a low-powered laser 4-31 Secondary Storage Flash Memory Nonvolatile memory with no moving parts But the electronics can wear out Available as Flash Insert these into a flash port of a camera, handheld PC, smartphone Flash memory cards memory sticks A form of flash memory that plugs into a memory stick port Flash memory drives A finger-sized module of flash memory Plugs into the USB port of most PCs and Macintoshes 4-32 Secondary Storage Online Secondary Storage Allows you to use the internet to back up your data Sign up with a vendor and receive access to software that allows you to upload your data to that company’s server Files should be encrypted to maintain security Use only for vital files that require immediate availability Use tape, removable hard disk cartridges, zip disks, optical storage or tape for normal backup 4-33 Future Developments in Processing & Storage Moore’s Law Gordon Moore predicted the number of transistors on a silicon chip will double every 18 months It has held up since the 1960s! 4-34 Future Developments in Processing & Storage Description of Processing Technology New Technology 1. M-RAM 1. 2. OUM 2. 3. Nanotechnology 3. Optical Computing 5. DNA Computing 6. Quantum Computing 4. 4. 5. 6. Magnetic RAM uses miniscule magnets rather than electrical charges Ovonic Multiplied Memory stores bits by generating different levels of low and high resistance on a glossy material Tiny machines work at a molecular level to make nanocircuits Uses lasers and light, not electricity Uses strands of synthetic DNA to store data Based on quantum mechanics and stores information using particle states 4-35 Future Developments in Processing & Storage New Technology 1. Higher-density disks Description of Storage Technology 1. Magnetic disk drives currently hold 100 GB of data Blank CDs are replacing floppy disks since they hold 650MB and cost < $1 each b. DVD disks hold up to 4.7 GB of data currently c. Perpendicular recording technology allows 25% - 100% more data to be stored on the same disk 2. Polymer memory creates chips that store data on plastics a. Nonvolatile memory b. Data is stored based on polymer’s electrical resistance a. 2. Molecular electronics 4-36